The present invention refers to a heat exchanger plate according to the preamble of claim 1. The invention also refers to a plate heat exchanger according to the preamble of claim 10.
The invention refers to heat exchanger applications for relatively viscous media, which may contain particles, fibres or other difficult components. The invention may advantageously be used in for instance the following application fields: Destilleries, sugar mills, paper industry, textile industry, food industry, pharmaceutical industry etc. In large plate heat exchangers intended for relatively viscous media within said application fields, the size or the flow area of the portholes are of determining significance for avoiding large pressure drops. Relatively large inlet ports may be obtained in that the porthole edge is located close to the gasket groove. In the area between the gasket groove and the porthole edge, there is a corrugation which forms a wall towards the gasket groove and which ensures that the gasket is held in place in the gasket groove. If the size of the porthole is maximised, this corrugation will extend to the porthole edge so that this obtains a corrugated or wave-like shape seen from the centre of the porthole.
In the applications mentioned above, it is at the same time important to prevent the media, which may contain particles, fibres etc, from getting attached to the porthole edge. If the porthole edge is corrugated, the risk that particles or fibres will get attached increases.
If the porthole edge, in order to avoid this risk, is given an even shape, the problem of a decreasing flow area is instead arising since this even area has to extend inwards and towards the centre of the porthole from the above defined corrugation.
GB-A-2107845 discloses a heat exchanger plate for a plate heat exchanger. The heat exchanger plate comprises a heat transfer area, and edge area, which extends around and outside the heat transfer area, and a number of portholes, which extend through the heat exchanger plate and are located inside and in the proximity of the edge area. The portholes are defined by a porthole edge and have a centre. The porthole edge has a first edge portion, which faces the area, and a second edge portion, which faces the heat transfer area.